#include <stdio.h>
#include <limits.h>
typedef unsigned float_bits;
float_bits float_i2f(int i)
{
unsigned u = (unsigned)i;
if(!u)
return 0u;

unsigned sign = u>>31;
unsigned exp,frac,f;
if(sign)
u=(~u)+1;
unsigned j,leftmost_one;
for(j=0;j<32;j++)
{
leftmost_one=u&(0x80000000>>j);
if(leftmost_one)
break;
}
exp = 158u-j;
f = u<<j<<1;
unsigned last_bit=(f&0x200)>>9;
unsigned truncation = f&0x1ff;
if(truncation<0x100)
frac = f>> 9;
else if(truncation >0x100)
frac= (f>>9)+1;
else
{
if(last_bit)
frac = (f>>9)+1;
else
frac = f>>9;
}
if(frac >>23)
{
++exp;
frac=0;
}
return (sign<<31)|(exp<<23)|frac;

}
int main()
{
int i;
unsigned r;
float f,fr;
for(i=INT_MIN;i<=INT_MAX;i++)
{
r=float_i2f(i);
fr=*((float*)&r);
f=(float)i;
if(fr == f)
printf("%d:ok\n",i);
else
{
printf("%d: %f %f error\n",i,f,fr);
return -1;
}
}
}

